Base for a writing instrument
FIG. 1 is a perspective view of a base for a writing instrument showing my new design; 
     FIG. 2 is a right side elevational view, the left side being a mirror image thereof; 
     FIG. 3 is a top plan view thereof; 
     FIG. 4 is a bottom plan view thereof; 
     FIG. 5 is a front elevational view thereof; 
     FIG. 6 is a rear elevational view thereof. 
     The writing instrument in FIG. 1 and the cord fragment in FIGS. 1 through 6 are depicted by means of broken lines for illustrative purposes only and form no part of the claimed design.